Expression heterogeneity research of ITGB3 and BCL-2 in lung adenocarcinoma tissue and adenocarcinoma cell line

High Expression of UBB, RAC1, and ITGB1 Predicts Worse Prognosis among Nonsmoking Patients with Lung Adenocarcinoma through Bioinformatics Analysis

Purpose

The molecular mechanism underlying the tumorigenesis and progression of lung adenocarcinoma (LUAD) in nonsmoking patients remains unclear. This study was conducted to select crucial therapeutic and prognostic biomarkers for nonsmoking patients with LUAD.

Methods

Microarray datasets from the Gene Expression Omnibus (GSE32863 and GSE75037) were analyzed for differentially expressed genes (DEGs). Gene Ontology (GO) enrichment analysis of DEGs was performed, and protein-protein interaction network was then constructed using the Search Tool for the Retrieval of Interacting Genes and Cytoscape. Hub genes were then identified by the rank of degree. Overall survival (OS) analyses of hub genes were performed among nonsmoking patients with LUAD in Kaplan-Meier plotter. The Cancer Genome Atlas (TCGA) and The Human Protein Atlas (THPA) databases were applied to verify hub genes. In addition, we performed Gene Set Enrichment Analysis (GSEA) of hub genes.

Results

We identified 1283 DEGs, including 743 downregulated and 540 upregulated genes. GO enrichment analyses showed that DEGs were significantly enriched in collagen-containing extracellular matrix and extracellular matrix organization. Moreover, 19 hub genes were identified, and 12 hub genes were closely associated with OS. Although no obvious difference was detected in ITGB1, the downregulation of UBB and upregulation of RAC1 were observed in LUAD tissues of nonsmoking patients. Immunohistochemistry in THPA database confirmed that UBB and ITGB1 were downregulated, while RAC1 was upregulated in LUAD. GSEA suggested that ribosome, B cell receptor signaling pathway, and cell cycle were associated with UBB, RAC1, and ITGB1 expression, respectively.

Conclusions

Our study provides insights into the underlying molecular mechanisms of the carcinogenesis and progression of LUAD in nonsmoking patients and demonstrated UBB, RAC1, and ITGB1 as therapeutic and prognostic indicators for nonsmoking LUAD. This is the first study to report the crucial role of UBB in nonsmoking LUAD.

miR-338 inhibits the metastasis of lung cancer by targeting integrin β3

miR-338 as an intronic miRNA from apoptosis-associated tyrosine kinase (AATK) is involved in tumor proliferation and apoptosis, but its function and regulatory mechanism in lung cancer is still obscure. In the present study, we found that miR-338 was strikingly downregulated in 115 lung cancer tissues and 5 lung cancer cell lines. Besides, low level of miR-338 was associated with tumor emboli, TNM stage, tumor recurrence and poor survival. Regaining the expression of miR-338 in lung cancer cell lines significantly impaired cellular adhesion, migration, invasion and lung tumor formation in nude mice. Furthermore, we also identified a metastasis related protein, integrin β3 (ITGB3), as a novel target gene of miR-338. Our results reveal a new regulatory mechanism of miR-338 which may help us better understand the metastasis of lung cancer.

Die-hard survivors: heterogeneity in apoptotic thresholds may underlie chemoresistance

The unmatched efficacy of microtubule-targeting agents (MTAs) as chemotherapeutics was once assumed to originate from their impact on mitotic processes; however, this misconception is being eroded by amassing data that MTAs instead target interphase functions in patients' tumors. What remains murky is how MTAs target malignant cells over non-malignant ones if proliferation rates do not distinguish them. In many instances, malignant cells are actually more 'primed' for apoptosis than non-malignant ones. Nevertheless, even if most cells within the tumor are more apoptosis-susceptible than those in healthy tissues, there likely exist small subpopulations of apoptosis-resistant clones that engender incomplete responses to MTAs and relapse. Therefore, intratumor heterogeneity in terms of proximity to the apoptotic threshold must be better understood to facilitate the design of chemotherapeutic regimens, which may benefit from including drugs like BH3 mimetics that help in lowering the apoptotic threshold of tumor cells within these chemoresistant subpopulations.